Your Job May Affect How Your Brain Ages

Zoe Middleton poses by a work titled “My Soul” by artist Katherine Dawson — a laser etched in lead crystal glass of the artist’s own MRI scan — at the exhibition “Brains: The Mind as Matter” at the Wellcome Collection in London.

Previous studies have suggested that people who engage in mentally stimulating activities are less likely to experience cognitive decline as they get older. For instance, reading, playing musical instruments, dancing and playing board games were associated with a lower risk of dementia among participants in the Bronx Aging Study. Based on studies like those, psychologist Alan Gow and his colleagues at University of Edinburgh decided to examine whether occupation influenced cognitive abilities in later life.

The research team enlisted participants from the Lothian Birth Cohort study of 1936, a group of Scottish people born in that year who had undergone cognitive testing in 1947 as part of an effort to find out whether intelligence among U.K. residents was dropping (the results showed it wasn’t). Gow and his colleagues recruited 1,066 people — almost evenly split between men and women — from the the original cohort and gave them a battery of tests for memory, processing speed and general cognitive ability. They also collected information about participants’ professions during their working lives and used the Dictionary of Occupational Titles to assign each profession a score for the job’s complexity in dealing with three factors — data, people and things.

The results showed that people whose jobs required complex work with data or people scored higher at age 70 on cognitive ability measures than those whose careers had not required that kind of cognitive engagement (a list of occupations that scored high on these measures is at the bottom of this post). Complex tasks involving things did not seem to offer the same mental boost. Examples of complex task involving data include synthesizing or coordinating numbers. Instructing and negotiating were two of the tasks rated as complex when it came to dealing with people.

It’s hardly surprising that workers whose jobs require complex thinking skills perform better on tests of cognitive ability — those jobs are likely to attract people who are naturally good at those tasks. What’s intriguing about this study is that the researchers were able to account for the study subjects’ cognitive ability in childhood — before they’d been shaped by higher learning or their professions. When they accounted for participants’ scores on the intelligence tests they’d taken at age 11, the link between complex jobs and cognitive ability in later life became weaker, but it didn’t disappear. The effect wasn’t enormous, but it’s on the order of other lifestyle factors associated with enhanced cognitive ability in later life. “The beneficial effect of more complex work with data or people was about the same as not smoking,” Gow said.

Still, some caveats remain. The researchers only considered occupational complexity in their analysis, so they may have missed other occupational factors that could affect later cognitive abilities, including support from co-workers and hazardous exposures. The study didn’t measure how engaged the participants were in their jobs, and it’s possible that some people with professions that rated high for certain demands weren’t actually challenged in these areas, while others may have had jobs that provided mental stimulation not captured in the job scores. It’s also possible that some participants in low-scoring professions were cognitively enriched by other aspects of their lives.

It’s not clear how participating in mentally engaging tasks protects against age-related cognitive decline, but one theory proposes that brain function can be built up through activity in the same way that weightlifting builds muscle strength. Challenging your brain with cognitively demanding tasks, the theory goes, can shore up your so-called cognitive reserve, giving you something to fall back on as age-related changes in the brain begin to accumulate. Gow and his colleagues are now following up with their study group to find out how long the effects they found might last.

Occupations Scored As High Cognitive Engagement

Agronomist

Animal breeder

Architect

Astronomer

Biologist

Cardiologist

Cartoonist

Civil engineer

Computer programmer

Counselor

Crossword puzzle maker

Editor

Entomologist

Family practice doctor

Fashion designer

Geneticist

Graphic Designer

Horticulturist

Humorist

Industrial designer

Interior designer

Judge

Lawyer

Magistrate

Meteorologist

Musician

Painter (artist)

Pathologist

Photojournalist

Physician

Playwright

Poet

Police artist

Probation officer

Psychologist

Range manager

Reporter

Sculptor

Social worker

Software engineer

Still photographer

Surgeon

Toxicologist

Christie Aschwanden is FiveThirtyEight’s lead writer for science. Her book “Good to Go: What the Athlete in All of Us Can Learn from the Strange Science of Recovery” is available here. @cragcrest